We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Combined toxicity of polyethylene microplastics and soil salinization to earthworms is generally antagonistic or additive
Summary
Researchers studied the combined effects of polyethylene microplastics and salt stress on earthworms and found that their interaction was generally antagonistic or additive rather than synergistic. Smaller microplastic particles triggered stronger avoidance behavior, while larger particles had little effect on their own. The findings suggest that in real-world soils where microplastics and salinity co-occur, their combined toxicity to soil organisms may not be worse than either stressor alone.
Microplastic (MP) accumulation and salinization frequently co-occur in terrestrial ecosystems, posing potential risks to soil health. However, their combined toxicity to soil invertebrates remains unclear. This study investigated combined effects of NaCl and polyethylene MPs (< 35, < 125, < 500 μm) on earthworms. The non-saline avoidance EC for < 35 μm MPs was 18 wt%, while avoidance only occurred at 50 wt% for < 125 μm MPs and not at all for < 500 μm MPs. Synergistic effects between NaCl and small MPs increased avoidance. High (10 wt%) MP concentrations by themselves did not increase earthworm mortality; mortality was lower with both MPs and 4000 mg/kg NaCl than with NaCl alone. Co-exposure to MPs and 1000 mg/kg NaCl further reduced growth rates by 16 % but increased cocoon production by 259 % compared to NaCl exposure alone. NaCl exposure induced earthworm oxidative and osmotic stress; overall stress levels were unchanged by MP co-exposure. 16S rRNA gene sequencing revealed that both NaCl and MPs significantly altered earthworm gut microbiome, suggesting potential impaired gut health. MPs more strongly impacted gut microbial community and functions when no salt was added. Overall, combined effects of NaCl and MPs on earthworms are mainly additive or antagonistic.
Sign in to start a discussion.
More Papers Like This
Combined toxicity of polyethylene microplastics and nickel oxide nanoparticle on earthworm (Eisenia andrei): oxidative stress responses, bioavailability and joint effect
Researchers studied the combined toxicity of polyethylene microplastics and nickel oxide nanoparticles on earthworms over 28 days. They found that smaller microplastics caused greater oxidative stress, and the combination of both pollutants was more harmful than either one alone. The study suggests that the co-occurrence of microplastics and metal nanoparticles in soil can amplify negative effects on soil-dwelling organisms.
Distinct responses of Caenorhabditis elegans to polyethylene microplastics and plant secondary metabolites
Researchers studied how polyethylene microplastics and plant-derived chemical compounds individually and together affect the roundworm C. elegans, a common soil organism. They found that while the plant compounds reduced worm reproduction and lifespan, microplastics had milder individual effects but modified the toxicity of the plant chemicals when combined. The study reveals that in real soil environments, the interactions between microplastics and natural plant chemicals create complex toxicity patterns.
Combined ecotoxicological effects of different-sized polyethylene microplastics and imidacloprid on the earthworms (Eisenia fetida)
Researchers exposed earthworms to different sizes of polyethylene microplastics combined with the pesticide imidacloprid and found that particle size significantly influenced the combined toxic effects. Smaller microplastics tended to increase pesticide toxicity more than larger ones, affecting earthworm survival, growth, and antioxidant responses. The findings highlight how microplastic size matters when assessing the joint environmental risks of plastic pollution and agricultural chemicals in soil.
Effects of polyethylene microplastics stress on soil physicochemical properties mediated by earthworm Eisenia fetida
Researchers exposed earthworms to polyethylene microplastics of two sizes and found that smaller particles (13 micrometers) were more toxic than larger ones (130 micrometers), reducing survival and growth more severely. The microplastics caused oxidative stress in the worms and altered key soil properties including pH and organic carbon content. Since earthworms play a vital role in maintaining healthy soil for agriculture, this damage could affect soil quality and ultimately the food grown in microplastic-contaminated farmland.
Combined toxicity of organophosphate flame retardants and polyethylene microplastics on Eisenia fetida: Biochemical and molecular insights
Researchers exposed earthworms to polyethylene microplastics, chlorinated flame retardants, and their combinations to assess combined toxicity effects. They found that the most toxic flame retardant (TDCPP) had its effects reduced when combined with microplastics, likely because the plastics absorbed the chemical and lowered its bioavailability. In contrast, microplastics enhanced the toxicity of another flame retardant (TCPP), demonstrating that microplastics can act as both carriers and modulators of co-contaminant toxicity in soil ecosystems.